The carrier was transferred to the United Kingdom on 22 December 1943 and commissioned into Royal Navy service the same day as HMS Ruler, with the pennant number D72.

After completing sea trials HMS Ruler went to Burrard Dry Dock, in Vancouver, British Columbia, Canada, for refit to Royal Navy standards, as a transport carrier.

HMS Ruler later made a third trip, fetching Grumman F6F Hellcat and Vought F4U Corsair from Norfolk, Virginia, between 20 and 29 October, this time arriving at Greenock to unload on 18 November.

[1] HMS Ruler served in the North Atlantic during 1944, protecting the vital flow of men and war materiel from the United States to Great Britain and to fighting fronts on the European continent.

[3] Propulsion was provided by two boilers which were connected to a steam turbine; it drove a shaft giving 9,350 brake horsepower (SHP), which could propel the ship at 16.5 knots (30.6 km/h; 19.0 mph).